Nitroanilines having chlorine substituents have been used as starting materials for a variety of products such as drugs, dyes and pesticides, e.g., 2,6-dichloro-4-nitroaniline (DCNA), is known to be active against certain soil, foliar and fruit pathogens on ornamental and agricultural crops.
In general, the prior processes used aqueous solutions of the strong inorganic acids such as hydrochloric or hypochlorous acid or their salts such as alkali hypochlorite. Subsequent treatments of the product are typically performed with relatively large volumes of aqueous solutions. The resulting aqueous effluent is a potential environmental pollutant which must be processed prior to disposal. The processing of the total aqueous effluent can be time consuming and represents an additional cost in the manufacture of the chlorinated products. Furthermore, the combined volume of aqueous effluent from the reaction itself and the subsequent washings of the product are difficult to process for recycling. It would be desirable to have a process for chlorinating nitroanilines which produces minimal aqueous effluent and provides a product which can be handled in a convenient, economical manner. It would also be desirable to have a method of reusing the reaction effluent in subsequent reactions.
The object of this invention is to provide a process for the chlorination of nitroaniline which reduces or eliminates noxious aqueous effluent and its related disposal problems.
It is a further object of this invention to provide a process for the chlorination of nitroanilines wherein the effluent is conveniently reused in subsequent chlorination reactions.